1. Field of the Invention
The present invention relates to a method for producing a resin plated product by applying an electroplating process to a resin molded product having an edge part and a resin molded product to be plated used for this method.
2. Related Art
When the resin plated product is produced, an electro-less plated thin film is formed on the surface of a resin molded product, and then, an electroplated thick film is formed by carrying out a plurality of processes. The resin plated product to which such plating processes are applied shows metallic luster depending on the kinds of plating components.
When an electroplating process is carried out, the resin molded product is held by a jig, immersed in an electroplating bath having an anode electrode, an anode voltage is applied to the anode electrode and a cathode voltage is applied to the resin molded product through the jig.
The resin molded product such as a molding for decorating a vehicle body includes an edge part having a relatively long form and sharp in the shape of an acute angle at an end. When the electroplated film is formed in the resin molded product having such an edge part, an electric charge in electroplating solution is liable to be concentrated to the edge part. Therefore, a quantity of plating deposited on the edge part is increased and the thickness of a plated film in the edge part is larger than that of other part. For instance, when the thickness of an electroplated film of other part than the edge part is 50 μm, the thickness of an electroplated film of the edge part may be sometimes possibly 100 μm or more. When the thickness of the plated film of the edge part is increased as described above, an external appearance of the product is deteriorated.
In order to solve the above-described problem, usually, for instance, JP-UM-A-3-45968, JP-A-2006-249492 and JP-UM-B-4-17570 disclose that an auxiliary cathode is provided in a jig and the auxiliary cathode is arranged in a plating bath in the vicinity of an edge part of a resin molded product.
Further, JP-A-7-228992 discloses that both right and left end parts of an anode electrode are covered with a resin shield plate of an L shape in section in an electroplating bath to shield the concentration of a current from the anode electrode to both the end parts of a resin molded product.
However, in JP-UM-A-3-45968, JP-A-2006-249492 and JP-UM-B-4-17570, as the number of times of using the jig is increased more, a large quantity of an electroplated film sticks to the auxiliary cathode formed in the jig. The electroplated film sticking to the auxiliary cathode is hardly completely peeled off from the auxiliary cathode. Accordingly, when the jig is taken in and out from a plating bath, the plated film falls from the auxiliary cathode and platting metal powder thereof adheres to a resin plated product, resulting in the deterioration of the external appearance of the resin plated product.
Further, the resin shield plate of JP-A-7-228992 is L shaped in section and large in its width. Since the resin shield plate is not electrically conductive, a plated film is not deposited. Therefore, when the resin shield plate is taken out from a plating bath, plating liquid remains on the resin shield plate. Accordingly, during moving the resin shield plate, the plating liquid remaining on the resin shield plate drops. Thus, plating liquid components stick to a resin plated product, so that the external appearance of the product may be sometimes deteriorated.